I've just added a K&N panel filter to the standard airbox and also fitted a much less restrictive Piper cold air feed too. It's on a Vectra 2.2 SRi shown below.
Now, it sounds quiter on idle, throatier on acceleration and also feels like it revs a lot faster too. I'm assuming any noticable gain is pyschological due to the increase in noise it makes. You can't really detect an increase of 1hp on the road can you?
Now, it sounds quiter on idle, throatier on acceleration and also feels like it revs a lot faster too. I'm assuming any noticable gain is pyschological due to the increase in noise it makes. You can't really detect an increase of 1hp on the road can you?